Carbamylalkyl phosphates and method of preparation



Patented Jan. 16, i hfi cans ' KYL PHOSPHATES AND METHOD OF PREPARATION Jack '1. @assaday and Erick I. Hoegberg, Stam- 80rd, and Bruce D. Gleissner, Riverside, Conn, assignors to American Cyanamid Company, New York, N. Y., a corporation of Maine No Drawing. Application February 4, 1948, Serial No. 6,348

13 Claims. (Cl. 260-461) in which R1 and R: are chosen from the group consisting of aliq'l, aralkyl, and aryl (in this specification and claims where the words aralkyl and aryl are used, they are intended to mean aralkyl hydrocarbon and aryl hydrocarbon respectively) radicals, R: and R4 are members of the group consisting of hydrogen, alml, hydroxyalkyl, aryl, and nitroaryl (in this specification and claims the word nitroaryl is intended to mean nitro substituted aryl hydrocarbon) radicals, X1, 2%, and & are members of the group consisting of sulfur and oxygen, and m represents a small whole number.

In the new compounds. R1 and B: may be the same or different radicals. Furthermore, it is to be understood that when R1 and R2 stand for alkyl radicals, they represent both the straight chain and branch chain, the saturated and unsaturated, and the cycloaliphatic hydrocarbon radicals. The R1 and R: radicals may also carry halogen subs'tituents, particularly chlorine and bromine. Typical examples of these radicals are methyl, ethyl, n-propyl, isopropyl, isobutyl, sec.- amyl, n-hexyl, 2-ethylhexyl, n-octyl, n-decyl. ndodecyl, oleyl, cetyl, ceryl, allyl, bromomethyl, z-chloroethyl, cyclohexyl, benzyl. phenyl, p chlorophenyl, o, m and p-nitrophenyl.

The compounds of this invention possess general pest-control characteristics, including insecticidal, rodenticidal, and fungicidal properties. They may also be employed as corrosion inhibitors, plasticizers, flotation agents, and petroleum additives.

The phosphate esters of the above general formula, when the symbol m stands for oiwgen. may be readily prepared by reacting a. phosphate of the general formula:

2 in which R1, R2, X1, and X2 have the meaning shown above, and Y represents an alkali-forming metal, with a halogen-substituted amide of the general formula in which R3, R4, and m have the meaning shown above, and Z is a member of the group consisting of chlorine and bromine.

The term alkali-forming metal as used in this specification and in the appended claims is intended to cover the alkali metals (including ammonium), and the alkaline earth metals.

A typical reaction in which sodium O,Ci-diethyl dithiophosphate is reacted with chloroacetamide to produce S-carbamylmethyl 0,0-diethyl dithio phosphate may be illustrated as follows:

CaHa

MHz High yields of the desired products are obtained by carrying out the reaction in the presrate, and isopropyl butyrate; saturated aliphatic nitriles such as acetonitrile and propionitrile; dioxane, nitrobenzene, chlorobenzene, toluene, xylene, chloroform, carbon tetrachloride, 1,2- dimethoxyethane, and the trialkyl' phosphates such as trimethyl phosphate, triethyl phosphat and triisopropyl phosphate.

The reaction is preferably carried out at a temperature within the range of from about201 to C. However, temperatures outside-got this range may be employed depending upon the type of reactants and solvents utilized.

memes An alternative method of preparing the above compounds consists in employing in lieu of the alkali-forming metal phosphate the corresponding acid and a basic alkali-forming metal compound, the latter having sufllcient alkalinity to neutralize said acid. Obvious1y, this procedure avoids the initial preparation and isolation of the alkali-forming metal phosphate. Such basic A3131 The phosphate esters of the above general formula, when the symbol X1 stands for sulfur. may be prepared by reacting a cyanoalkyl phosphate of the general formula in which R1, R2, X1. X2, and m have the meaning shown above, with either hydrogen sulfide or a mercaptan, preferably in a closed vessel under pressure.

The cyanoalkyl phosphates utilized in the preceding reaction may be prepared by reacting a phosphate of the general formula in which R1, R2, X1, X2, and Y have the meaning shown above, with a halogen-substituted nitrile of the general formula Z--(CH2) m-CN in which m and Z have the meaning shown above.

The following examples will further illustrate the invention.

Example 1 41.6 rams (0.2 mol.) of sodium 0,0-diethyl dlthiophosphate, 18.7 grams (0.2 mol.) of chloroacetamide, and 250 cc. of acetone were mixed together and allowed to stand at room temperature (20 C.) for 24 hours. The precipitated sodium chloride was filtered oil and the filtrate heated under vacuum to remove the acetone. The resid- 4 us] crystalline product, S-carbamylmethyl, 0.0- diethyl dithiophosphate, weighing 46 grams (95% yield) was recrystallized from 125 cc. of carbon tetrachloride. The recrystallized product was a colorless crystalline solid, meltingat 5748" C.

' Example 2 The procedure of Example 1 was employed, using 62.4 grams of sodium 0,0-diethyl dithiophosphate, 51 grams of chloroacetanilide, and 400 cc. of acetone. 91 grams of crude 0,0-diethyl S- (N-phenylcarbamyl) methyl dithiophosphate were obtained. After recrystallization from heptane, the product was a colorless crystalline material melting at 8547" C.

Example 3 The procedure of Example 1 was employed using 41.6 grams of sodium 0,0-diethyl dithiophosphate, 42.9 grams of alpha-chloro-4-nitroacetanilide, and 250 cc. of acetone. 69 grams (95% yield) of 0.0-diethyl S-(N-p-nitrophenyl carbamyl) methyl dithiophosphate were obtained. After recrystallization from 500 cc. of carbon tetrachloride, the product was a colorless crystalline material melting at 109-110 C.

Example 4 62.4 grams of sodium 0,0-diethyl dithiophosphate, 32.3 grams of beta-chloropropionamide, and 400 cc. of acetone were mixed together and allowed to stand at room temperature for 24 hours. The precipitated sodium chloride was filtered off and the filtrate heated under vacuum to remove the acetone. The residual product, 8- 2-carbamylethyl 0.0-diethyl dithiophosphate, weighing grams, was a clear, light brown liquid having a refractive index a 1.5230.

Example 5 The procedure of Example 4 was employed using 14.4 grams of sodium 0,0-diethyl dithiophosphate, 7.4 grams of beta-chloropropionanilide, and 100 cc. of acetone. The residual product, 0,0-diethyl S-(2-N-phenylcarbamyl) ethyl dithiophosphate, weighing 20.8 grams (90% yield) was an amber-colored oil having a refractive index n 1.5468. 4

Example 6 The procedure of Example 4 was employed using 62.4 grams of sodium 0,0-diethy1 dithio- .phosphate, 37.1 grams of alpha-chloro N-(hydroxymethyl) acetamide, and 250 cc. of acetone. The mixture was heated under reflux for a period of 6 hours. The residual product, 0,0-diethyl B-(N-hydroxymethyl) carbamylmethyl dithiophosphate, was a straw-colored, viscous liquid having a refractive index a 1.5372.

Example 7 42.9 grams of 0,0-dimethyl dithiophosphoric acid were added slowly to a well-agitated mixture of 28.7 grams of anhydrous sodium carbonate suspended in 100 cc. of methyl isobutyl ketone. The mixture was then heated to about 65 C. and 25.3 grams of chloroacetamide were added. The resulting mixture was held at 80 C. for one hour with continued stirring, then cooled to room temperature and filtered. The filtrate was washed twice with water, dried over anhydrous sodium sulfate, and filtered. The filtrate was heated under vacuum to remove the methyl isobutyl ketone. The residual product, S-carbamylmethyl 0,0-dimethyl dithiophosphate, was a colorless crystalline solid melting at 60-'-62 C.

Example 8 48.4 grams of 0,0-dibutyl dithiophosphoric acid were added slowly to a well-agitated mixture of 21.2 grams of anhydrous sodium carbonate suspended in 200 cc. of acetone. 18.7 grams of chloroacetamide were then added. The reaction mixture was stirred for two hours, allowed to stand at room temperature (20-22 C.) for 24 hours, filtered, and the filtrate stripped of solvent under vacuum. The residual brown oil was washed twice with dilute sodium carbonate solution, then with water, and dried over anhydrous sodium sulfate. The product, 0,0-di-n-butyl S-carbamylmethyl dithiophosphate, was an amoer-colored, viscous oil having a refractive index a 1.5111.

- Example 10 The procedure of Example 9 was employed ising 28.2 grams of 0,0-diphenyl dithiophos- :horic acid, 10.6 grams of anhydrous sodium :arbonate, 100 cc. of methyl isobutyl ketone. and i4 grams of chloroacetamide. The reaction mixvure was stirred and heated at 75-80 C. for a :eriod of 4 hours. 23 grams of S-carbamylmethyl ),O-diphenyl dithiophosphate were obtained. the product was a red, viscous oil having a reractive index a 1.5988.

I Example 11 18.3 grams of n-butyl amine, 26.5 grams of anhydrous sodium carbonate, and 200 cc. oi methyl isobutyl ketone were mixed together and ooled in an ice-bath. 28.3 grams of chloroacetyl hloride were added with stirring during a period f one hour, the temperature being held at 10- 2" C. The mixture was then warmed slowly to 5 C. and maintained at this temperature for V2 hours, after which it was allowed to cool to 6 C. 26.5 grams of anhydrous sodium carbonate rere then added, followed by the addition of 50 rams of 0,0-diethyl dithiophosphoric acid. The iixture was held at 85 C. for 3% hours, cooled J room temperature, and filtered. The filtrate was washed several times with water, then with iturated sodium bicarbonate solution, and dried ver anhydrous sodium sulfate. The methyl isoutyl ketone was removed by distillation under zduced pressure. The residual product, S-(N- utylcarbamyDmethyl 0,0-diethyl dithiophos hate, was a light brown oil having a refractive idex a 1.5057.

Example 12 56.1 grams of potassium hydroxide were dislved in 400 cc. of ethyl alcohol cooled in an e-bath. 86 grams of diethyl chlorophosphate ere added drop-wise with stirring, the temperalre being held at i0-15 C. The mixture conining potassium diethyl phosphate and precipi- .ted potassium chloride was warmed to 35 0. 1d 46.8 grams of chloroacetamide were then ided. The reaction mixture was heated to 50 C. 1d stirred for /2 hour, then allowed to stand room temperature (26-22 C.) for 36 hours.

by filtration and the filtrate was strid of ethyl alcohol by distillation under vacuum. The residual product, carbamylmethyl diethyl phosphate, was a colorless oil having a refractive index 12 1.4280.

Example13 62.6 grams of potassium 0,0-diethyl thiophosphate and 28.1 grams of-chloroacetamide were dissolved in 250 cc. of methyl ethyl ketone. The

mixture was heated at 60 C. for 2 hours, cooled to room temperature, and filtered. The filtrate was stripped of the methyl ethyl ketone by distillation under vacuum. The residual product, carbamylmethyl 0,0-diethyl thlophosphate, was obtained in quantitative yield as an ambercolored, viscous liquid having a," refractive index a 1.4888. Example 14 50 grams of S-cyanomethyl 0,0-diethyl dithio- Phosphate and 7.6 grams of hydrogen sulfide were reacted together in a closed vessel in 100 cc. of

toluene in the presence of 1 gram of triethyl' amine (catalyst) at C. under a pressure of 100 lbs. per sq. in. for a period of 20 hours. The reaction mixture was poured into a shallow open vessel and the toluene allowed to evaporate oif, leaving a mixture of yellow crystals and a brown oil. The crystals were removed by filtration, and recrystallized from a 25% toluene-% hexane mixture with a small quantity of decolorizing charcoal. The product, 0,0-diethyl S-thiocarbamylmethyl dithiophosphate, was a colorless crystalline material melting at AW-47 C.

The phosphate esters of this invention may be employed in controlling many types of insects and mites such as, for example, the black bean aphid, green peach aphid, pea aphid, chrysanthemum aphid, greenhouse thrips, California red scale, citrus red spider, greenhouse red spider, 'milkweed bug, mealy bug, sow bug, German cockroach, southern army worm, yellow fever mosquito, malarial mosquito, Mexican bean bettle, confused flour beetle, and black carpet beetle.

These new compounds may also be used in combination with insecticides such as lead arsenate,

in He in which R1 and R2 are chosen from the group consisting of alkyl, arallryl, and aryl radicals, R3 and R4 are members of the group consisting of hydrogen, alkyl, hydroxyalkyl, aryl, and nitroaryl radicals, X1, X2, and X: are members of the group consisting of sulfur and owgen, and m be precipitated poum chloride was removed ?5 represents a small whole num.

games 2. B-carbamylmethyl 0,0-diethyl dithiophosphate.

3. S-carbamylmethyl 0,0-dimethy1 dithiophosphate.

4. 0,0-diethyl S-(N-hydroxymethyDcarbamylmethyl dithiophosphate.

5. A method of preparing a phosphate ester of the general formula in which R1 and R: are chosen from the group consisting of alkyl, aralkyl, and aryl radicals, R: and R4 are members of the group consisting of hydrogen, alkyl, hydroxyalkyl, aryl, and nitroaryl radicals, X1 and X: are members of the group consisting of sulfur and oxygen, and m represents a small whole number, which includes the step of reacting a phosphate of the general formula in which R1 and R: are chosen from the group consisting of alkyl, aralkyl, and aryl radicals, Xi and X: are members of the group consisting of sulfur and oxygen, and Y represents an alkalii'orming metal, with a halogen-substituted amide of the general formula in which R: and R4 are members of the group consisting of hydrogen, alkyl, hydroxyalkyl, aryl, and nitroaryl radicals, m represents a small whole number, and Z is a member of the group consisting of chlorine and bromine.

6. The method of claim in which the reaction is carried out in the presence of a solvent.

7. The method of claim 5 in which the reaction is carried out at a temperature within the range of from about 20-150 C. 1

8. A method of preparing a phosphate ester of the general formula in which R1 and R2 are chosen from the group consisting of alkyl, aralkyl, and aryl radicals, R3 and R4 are members of the group consisting of hydrogen, alkyl, hydroxyalkyl, aryl, and nitroaryl radicals, X1 and X: are members of the group 8 consisting of sulfur and oxygen, and or. represents a small whole number, which includes the step of reacting together a halogen-substituted amide of the general formula in which R: and R4 are members of the group consisting of hydrogen, alkyl, hydroxyalkyl, aryl, and nitroaryl radicals, 122. represents a small whole number, and Z is a member of the group consisting of chlorine and bromine, an acid phosphate of the general formula in which R1 and R: are chosen from the group consisting of alkyl, aralkyl, and aryl radicals, and X1 and & are members of the group consisting of sulfur and oxygen, and a basic alkali-forming metal compound having sufllcient alkalinity to neutralize the acid phosphate.

9. The method of claim 8 in which the basic alkali-forming metal compound is sodium carbonate.

10. The method of claim 8 in which the reaction is carried out in the presence of a solvent.

11. A method of preparing S-carbamylmethyi '0,0-diethyl dithiophosphate which includes the REFERENCES crrnn The following references are of record in the flie of this patent:

UNITED STATES PATENTS Number Name Date 2,266,514 Romieux et al Dec. 16, 1941 2,328,570 McNally et a1. Sept. '7. 1943 2,335,953 McCracken et al Dec. "1. 1943 

1. PHOSPHATE ESTERS OF THE GENERAL FORMULA 